#include <bits/stdc++.h>
using namespace std;
#define int long long
int N;
int x[314159];
int pref[314159];
int y[314159];
int sumy = 0;
int f(int n) {
if (n >= sumy) return -1234567890;
int ans = 0;
int xpos = 0;
int xtemp = x[0];
int lo = 0;
int hi = N;
int mid;
while (true) {
mid = (lo+hi)/2;
if (pref[mid] > n) hi = mid-1;
else if (pref[mid+1] <= n) lo = mid+1;
else break;
}
int ypos = mid;
int ytemp = y[ypos]-(n-pref[mid]);
int yposi = ypos;
int minus = ytemp;
bool b = false;
while (true) {
if (ypos >= N) {
b = true;
ypos -= N;
ytemp = y[ypos];}
if (ypos == yposi && b) ytemp -= minus;
if (xpos == N) break;
if (xtemp > ytemp) {
xtemp -= ytemp;
if (xpos > ypos) ans -= ytemp;
else if (xpos < ypos) ans += ytemp;
ytemp = y[++ypos];
}
else if (xtemp == ytemp) {
if (xpos > ypos) ans -= ytemp;
else if (xpos < ypos) ans += ytemp;
xtemp = x[++xpos];
ytemp = y[++ypos];
}
else {
ytemp -= xtemp;
if (xpos > ypos) ans -= xtemp;
else if (xpos < ypos) ans += xtemp;
xtemp = x[++xpos];
}
}
return ans;
}
int32_t main() {
cin >> N;
memset(x, 0, sizeof(x));
memset(y, 0, sizeof(y));
for (int i = 0; i < N; i++) cin >> x[i];
for (int i = 0; i < N; i++) {
cin >> y[i];
sumy += y[i];
}
if (N == 1) {
cout << 0;
return 0;
}
int sumx = 0;
for (int i = 0; i < N; i++) {
if (sumx == sumy) {
x[i] = 0;
continue;}
if (sumx + x[i] > sumy) {
x[i] = sumy-sumx;
sumx = sumy;
continue;
}
sumx += x[i];
}
pref[0] = 0;
for (int i = 0; i < N; i++) pref[i+1] = pref[i]+y[i];
//f(9);
//return 0;
if (sumx >= 2 && f(0) > f(1)) {
cout << f(0);
return 0;
}
if (sumx == 0) {
cout << 0;
return 0;
}
int lo = 0;
int hi = sumx-1;
int mid;
while (true) {
mid = (lo+hi)/2;
if (mid > 0 && f(mid) < f(mid-1)) hi = mid-1;
else if (mid < sumx-2 && f(mid) < f(mid+1)) lo = mid+1;
else break;
}
cout << f(mid);
return 0;
}
